As regards the remainder of this text, the word "laser" is taken both as an amplifier and an oscillator.
The invention can be used in telecommunications applications and in fusion applications controlled by means of magnetic containment.
Research relating to the physics of Tokamaks is particularly concerned with the following:
diagnostic methods (see document (1) which, like the other documents subsequently referred to, is mentioned at the end of this description immediately preceding the claims),
current generating methods (see documents (2) and (3)),
heating methods (see documents (4) and (5)), methods which require millimetric sources with power exceeding 1 MW in an almost continuous state.
The electromagnetic radiation sources able to be considered for such applications are mainly gyrotrons and free electron lasers, the latter being particularly known by virtue of the document (6) to be referred to subsequently.
Free electron lasers posses various advantages with respect to gyrotrons and especially frequency tunability and the possibility of covering the field of dwarf and sub-dwarf waves, far-infrared, etc., without requiring any major design modification.
A number of experiments have already been conducted on free electron lasers, one of which is mentioned in document (7). The present invention concerns a free electron laser able to emit a high-power electromagnetic radiation in the form of pulses with a much longer duration, for example an electromagnetic radiation with a power of greater than 1 MW within the spectral range extending from 150 GHz to about 300 GHz in the form of repetitive pulses in a continuous state and lasting more than one millisecond.